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Molecular nitrogen promotes catalytic hydrodeoxygenation


Although molecular dinitrogen (N2) is widely used as a carrier or inert gas for many catalytic reactions, it is rarely considered as a catalytic promoter. Here, we report that N2 could be used to reduce the activation energy for catalytic hydrodeoxygenation over ruthenium-based catalysts. Specifically, we report a 4.3-fold activity increase in the catalytic hydrodeoxygenation of p-cresol to toluene over a titanium oxide supported ruthenium catalyst (Ru/TiO2) by simply introducing 6 bar N2 under batch conditions at 160 °C and 1 bar hydrogen. Detailed investigations indicate that N2 can be adsorbed and activated on the metallic ruthenium surface to form hydrogenated nitrogen species, which offer protic hydrogen to lower the activation energy of direct carbonaromatic–oxygen bond scission and the hydrogenation of hydroxy groups. Thus, by employing different ruthenium catalysts, including Ru/TiO2, Ru/Al2O3, Ru/ZrO2 and Ru/C, we demonstrate that N2 promotion of hydrodeoxygenation can be regarded as a general strategy.

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Fig. 1: Structural characterization of the Ru/TiO2 catalyst.
Fig. 2: Catalytic performance promoted by N2 in the hydrodeoxygenation of p-cresol using the Ru/TiO2 catalyst.
Fig. 3: Understanding the promotion of HDO by N2.
Fig. 4: DFT calculations of the HDO reaction.
Fig. 5: Illustration of the combination of N2 activation and HDO reaction over Ru/TiO2.

Data Availability

The data that support the plots within this paper and other findings of this study are available from the corresponding author uon reasonable request.


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H.D. thanks SCG Chemicals, SCG Packaging (Thailand) and the National Natural Science Foundation of China (Grant No. 21978147). Y.Z. thanks the National Natural Science Foundation of China (Grant No. 21878008) and the Fundamental Research Funds for the Central Universities (BUCTRC201807). X.M. thanks the National Natural Science Foundation of China (21902182) and the Fundamental Research Funds for the Central Universities (2019QH01). J.D. acknowledges support from the Youth Innovation Promotion Association CAS. X.Z. thanks the National Natural Science Foundation of China (Grant No. 11875258). J.-C.B. thanks SCG Chemicals (Thailand) for funding. We also thank the Hefei Light Source and Shanghai Light Source for use of instruments and the Diamond Light Source for access and support in the use of the electron Physical Science Imaging Centre (EM16969, 17397), which contributed to the results presented here. J.L. thanks the National Natural Science Foundation of China (Grand Nos. 21433005, 91645203 and 21590792). The calculations were performed using the supercomputers at Tsinghua National Laboratory for Information Science and Technology. We also thank Y. Li for providing characterization resources and S. Ji for performing ICP analysis. We thank C. Chen for performing TPR measurement, W.-C. Lin for helping with the fixed-bed reactions and Y. Yang for assisting with the FTIR measurements.

Author information




H.D. conceived the idea, designed and carried out the synthesis, characterizations and catalytic reactions, analysed the data and wrote the manuscript. J.L. and X.M. performed DFT calculations and wrote the manuscript. Y.Z. carried out catalytic reactions and analysed the data. M.X. performed the in situ XPS and FTIR measurements and analysed the data. J.D, X.Z. and D.C. performed the in situ XPS measurements and data analysis. J.Z. helped design the experiments and analysed the data. C.A., M.D. and A.K. performed the TEM and STEM measurements. Y.-K.P. performed acidity analysis. T.I. conceived the idea and anticipated discussion. J.-C.B. regulated the experiments and anticipated discussion. J.L., S.C.E.T. and D.O.H. supervised the project, helped design the experiments, analysed the data and wrote the manuscript. All the authors commented on the manuscript and have given approval to the final version of the manuscript.

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Correspondence to Jun Li or Shik Chi Edman Tsang or Dermot O’Hare.

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Supplementary Figures 1–28, Tables 1–3, Notes 1 and 2 and References.

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Duan, H., Liu, JC., Xu, M. et al. Molecular nitrogen promotes catalytic hydrodeoxygenation. Nat Catal 2, 1078–1087 (2019).

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